This invention relates to inhibitors of cysteine proteases, in particular to dipeptide nitrile cathepsin inhibitors and to their pharmaceutical use for the treatment or prophylaxis of diseases or medical conditions in which cathepsins are implicated.
The cysteine cathepsins, e.g. cathepsins B, K, L and S, are a class of lysosomal enzymes which are implicated in various disorders including inflammation, rheumatoid arthritis, osteoarthritis, osteoporosis, tumors (especially tumor invasion and tumor metastasis), coronary disease, atherosclerosis (including atherosclerotic plaque rupture and destabilization), autoimmune diseases, respiratory diseases, infectious diseases and immunologically mediated diseases (including transplant rejection).
In accordance with the invention it has been found that dipeptide nitrites are particularly useful as cysteine cathepsin inhibitors and can be used for the treatment of the above-cited cysteine cathepsin dependent conditions.
Accordingly the present invention provides an N-terminal-substituted dipeptide nitrile, i.e. a dipeptide in which the C-terminal carboxy group of the dipeptide is replaced by a nitrile group (xe2x80x94Cxe2x89xa1N) and in which the N-terminal nitrogen atom is substituted via a peptide or pseudopeptide linkage which optionally additionally comprises a -methylene-hetero atom-linker or an additional hetero atom, directly by aryl, lower alkyl, lower alkenyl, lower alkynyl or heterocyclyl, or a physiologically-acceptable and -cleavable ester or a salt thereof, for use as a pharmaceutical.
The invention further provides a pharmaceutical composition comprising an N-terminal-substituted dipeptide nitrile as defined above as an active ingredient.
The invention also provides a method of treating a patient suffering from or susceptible to a disease or medical condition in which a cathepsin is implicated, comprising administering an effective amount of an N-terminal-substituted dipeptide nitrite as defined above to the patient.
The invention further includes the use of an N-terminal-substituted dipeptide nitrite as defined above for the preparation of a medicament for therapeutic or prophylactic treatment of a disease or medical condition in which a cathepsin is implicated.
The dipeptide nitrile of the invention conveniently comprises xcex1-amino acid residues, including both natural and unnatural xcex1-amino acid residues. Herein the xe2x80x9cnatural xcex1-amino acid residuesxe2x80x9d denote the 20 amino acids obtainable by translation of RNA according to the genetic code or the corresponding nitrites thereof, as appropriate. xe2x80x9cUnnatural xcex1-amino acid residuesxe2x80x9d are xcex1-amino acids which have xcex1-substituents other than those found in xe2x80x9cnatural xcex1-amino acid residuesxe2x80x9d. Preferred xcex1-amino acid residues, as the C-terminal amino acid residue of the dipeptide nitrite, are the nitrites of tryptophan, 2-benzyloxymethyl-2-amino-acetic acid, 2,2-dimethyl-2-amino-acetic acid, 2-butyl-2-amino-acetic acid, methionine, leucine, lysine, alanine, phenylalanine, and glycine and derivatives thereof, e.g. as hereinafter described. Preferred amino acid residues as the N-terminal amino acid residue of the dipeptide nitrite are 1-amino-cyclohexanecarboxylic acid, 1-amino-cycloheptanecarboxylic acid, phenylalanine, histidine, tryptophan and leucine and derivatives thereof, e.g. as hereinafter described.
The aryl, lower alkyl, lower alkenyl, lower alkynyl or heterocyclyl substituent (hereinafter referred to as R) is attached to the the N-terminal nitrogen atom of the dipeptide via a peptide linkage, i.e. as Rxe2x80x94C(O)xe2x80x94NHxe2x80x94, or via a pseudopeptide linkage. Suitable pseudopeptide linkages include sulphur in place of oxygen and sulphur and phosporous in place of carbon, e.g. as Rxe2x80x94C(S)xe2x80x94NHxe2x80x94, Rxe2x80x94S(O)xe2x80x94NHxe2x80x94, Rxe2x80x94S(O)2xe2x80x94NHxe2x80x94 or Rxe2x80x94P(O)2xe2x80x94NH and analogues thereof. Additionally the peptide or pseudopeptide linkage between the R substituent and the N-terminal nitrogen atom may comprise an additional hetero atom, e.g. as Rxe2x80x94Hetxe2x80x94C(O)xe2x80x94NHxe2x80x94, or a -methylene-hetero atom-linker, e.g. as Rxe2x80x94Hetxe2x80x94CH2xe2x80x94C(O)xe2x80x94NHxe2x80x94 or Rxe2x80x94CH2xe2x80x94Hetxe2x80x94C(O)xe2x80x94NHxe2x80x94, wherein Het is a hetero atom selected from O, N or S, and pseudopeptide containing alternatives thereof, e.g. as defined above. When the linkage between the aryl substituent and the N-terminal nitrogen atom comprises a -methylene-hetero atom-linker, the methylene group and the hetero atom may be optionally further substituted, e.g. as hereinafter described.
The R substituent may be further substituted, e.g. by up to 3 substituents selected from halogen, hydroxy, amino, nitro, optionally substituted C1-4alkyl (e.g. alkyl substituted by hydroxy, alkyloxy, amino, optionally substituted alkylamino, optionally substituted dialkylamino, aryl or heterocyclyl), C1-4alkoxy, C2-6alkenyl, CN, trifluoromethyl, trifluoromethoxy, aryl, (e.g. phenyl or phenyl substituted by CN, CF3, halogen, OCH3), aryloxy, (e.g. phenoxy or phenoxy substituted by CN, CF3, halogen, OCH3), benzyloxy or a heterocyclic residue.
Accordingly in preferred embodiments the invention provides a compound of formula I, or a physiologically-acceptable and -cleavable ester or a salt thereof 
wherein:
R is optionally substituted (aryl, lower alkyl, lower alkenyl, lower alkynyl, or heterocyclyl);
R2 and R3 are independently hydrogen, or optionally substitued [lower alkyl, cycloalkyl, bicycloalkyl, or (aryl, biaryl, cycloalkyl or bicycloalkyl)-lower alkyl]; or
R2 and R3 together represent lower alkylene, optionally interrupted by O, S or NR6, so as to form a ring with the carbon atom to which they are attached wherein R6 is hydrogen, lower alkyl or aryl-lower alkyl; or
either R2 or R3 are linked by lower alkylene to the adjacent nitrogen to form a ring;
R4 and R5 are independently H, or optionally substituted (lower alkyl, aryl-lower alkyl), xe2x80x94C(O)OR7, or xe2x80x94C(O)NR7R8,
xe2x80x83wherein
R7 is optionally substituted (lower alkyl, aryl, aryl-lower alkyl, cycloalkyl, bicycloalkyl or heterocyclyl), and
R8 is H, or optionally substituted (lower alkyl, aryl, aryl-lower alkyl, cycloalkyl, bicycloalkyl or heterocyclyl), or
R4 and R5 together represent lower alkylene, optionally interrupted by O, S or NR6, so as to form a ring with the carbon atom to which they are attached wherein R6 is hydrogen, lower alkyl or aryl-lower alkyl, or
R4 is H or optionally substituted lower alkyl and R5 is a substituent of formula xe2x80x94X2xe2x80x94(Y1)nxe2x80x94(Ar)pxe2x80x94Qxe2x80x94Z
xe2x80x83wherein
Y1 is O, S, SO, SO2, N(R6)SO2, Nxe2x80x94R6, SO2NR6, CONR6 or NR6CO;
n is zero or one;
p is zero or one;
X2 is lower alkylene; or when n is zero, X2 is also C2-C7-alkylene interrupted by O, S, SO, SO2, NR6, SO2NR6, CONR6 or NR6CO;
wherein R6 is hydrogen, lower alkyl or aryl-lower alkyl;
Ar is arylene;
Z is hydroxy, acyloxy, carboxyl, esterified carboxyl, amidated carboxyl, aminosulfonyl, (lower alkyl or aryl-lower alkyl)aminosulfonyl, or (lower alkyl or aryl-lower alkyl)sulfonylaminocarbonyl; or Z is tetrazolyl, triazolyl or imidazolyl;
Q is a direct bond, lower alkylene, Y1-lower alkylene or C2-C7-alkylene interrupted by Y1;
X1 is xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94P(O)(OR6)xe2x80x94
wherein R6 is as defined above;
Y is oxygen or sulphur;
L is optionally substituted xe2x80x94Hetxe2x80x94, xe2x80x94Hetxe2x80x94CH2xe2x80x94 or xe2x80x94CH2xe2x80x94Hetxe2x80x94,
wherein Het is a hetero atom selected from O, N or S, and
x is zero or one;
and aryl in the above definitions represents carbocyclic or heterocyclic aryl, for use as a pharmaceutical;
a pharmaceutical composition comprising a compound of formula I as defined above as an active ingredient;
a method of treating a patient suffering from or susceptible to a disease or medical condition in which a cathepsin is implicated, comprising administering an effective amount of a compound of formula I as defined above to the patient; and
use of a compound of formula I as defined above for the preparation of a medicament for therapeutic or prophylactic treatment of a disease or medical condition in which a cathepsin is implicated.
The invention also provides novel dipeptide nitriles.
Accordingly the invention further provides a compound of formula I as defined above
provided that when R is lower alkyl not substituted by aryl,
one of R4 or R5 is a substituent of formula xe2x80x94X2xe2x80x94(Y1)nxe2x80x94(Ar)pxe2x80x94Qxe2x80x94Z,
provided that when x is one, L is xe2x80x94Oxe2x80x94, or xe2x80x94CH2xe2x80x94Oxe2x80x94 and X1 is xe2x80x94C(O)xe2x80x94,
either one of R4 or R5 is a substituent of formula xe2x80x94X2xe2x80x94(Y1)nxe2x80x94(Ar)pxe2x80x94Qxe2x80x94Z, or R is not unsubstituted phenyl,
provided that when R2xe2x95x90R4xe2x95x90R5xe2x95x90H, x is zero and X1 is xe2x80x94C(O)xe2x80x94,
R3 is not H, xe2x80x94CH3, xe2x80x94CH(CH3)2, xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, xe2x80x94CH2xe2x80x94COOH, or xe2x80x94CH2xe2x80x94COOxe2x80x94CH2xe2x80x94CH3, when R is unsubstituted phenyl,
R3 is not H, xe2x80x94CH(CH3)2, or xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, when R is 4-aminophenyl or 4-nitrophenyl,
R3 is not H when R is 3-aminophenyl, 3-nitrophenyl 2-chloropyridin-4-yl, or vinyl or
R3 is not xe2x80x94CH2xe2x80x94CH2xe2x80x94Sxe2x80x94CH3 when R is pyridin-3-yl or 2-chloropyridin4-yl,
provided that when R2xe2x95x90R3xe2x95x90R4xe2x95x90H, x is zero and X1 is xe2x80x94C(O)xe2x80x94 and R is phenyl,
R5 is not xe2x80x94CH(CH3)2,
provided that when R3xe2x95x90R4xe2x95x90H, R5 is xe2x80x94CH2xe2x80x94CH2xe2x80x94COOH, x is zero and X1 is xe2x80x94C(O)xe2x80x94,
R2 does not form a heterocyclic ring with the adjacent nitrogen atom, and
provided that when R2xe2x95x90R3xe2x95x90R4xe2x95x90R5xe2x95x90H, x is zero and X1 is xe2x80x94SO2xe2x80x94,
R is not 4-methylphenyl.
In formula I R, R2, R3, R4, R5 and L may be further substituted by one or more, e.g. up to 3, substituents independently selected from lower alkyl, aryl, aryl-lower alkyl, cycloalkyl, heterocyclyl, xe2x80x94CN, -halogen, xe2x80x94OH, xe2x80x94NO2, xe2x80x94NR9R10, xe2x80x94X3xe2x80x94R7, lower alkyl-X3xe2x80x94R8, halo-substituted lower alkyl,
wherein R7 and R8 are as defined above,
X3 is xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94NR8xe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94C(S)Oxe2x80x94, xe2x80x94C(O)NR8xe2x80x94,
wherein R8 is as defined above,
R9 and R10 are independently as defined above for R8, or xe2x80x94X4xe2x80x94R8,
wherein X4 is xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94C(O)Oxe2x80x94, xe2x80x94C(S)Oxe2x80x94, xe2x80x94C(O)NR6xe2x80x94
wherein R6 and R7 are as defined above, or
R8 and R10 together with N form a heteroaryl group or a saturated or unsaturated heterocycloalkyl group, optionally containing one or more additional heteroatoms selected from O, N or S.
Compounds of formula I exhibit valuable pharmacological properties in mammals, in particular as cysteine cathepsin inhibitors. In accordance with the present invention it has been found that by appropriate choice of groups R, R2, R3, R4, R5, X1, Y and L, the relative selectivity of the compounds as inhibitors of the various cysteine cathepsin types, e.g. cathepsins B, K, L and S may be altered, e.g. to obtain inhibitors which selectively inhibit a particular cathepsin type or combination of cathepsin types.
In a first aspect the invention provides a compound of formula II, or a physiologically-acceptable and -cleavable ester or a salt thereof 
wherein:
R20 is optionally substituted (aryl, aryl-lower alkyl, lower alkenyl, lower alkynyl, heterocyclyl, or heterocyclyl-lower alkyl);
R22 is H, or optionally substitued lower alkyl, and
R23 is optionally substituted (lower alkyl, aryl-lower alkyl, or cyloalkyl-lower alkyl) or
R22 and R23 together with the carbon atom to which they are attached form an optionally substituted (cycloalkyl group or heterocycloalkyl group);
R24 and R25 are independently H, or optionally substituted (lower alkyl, or aryl-lower alkyl), xe2x80x94C(O)OR7, or xe2x80x94C(O)NR7R8 
wherein R7 and R8 are as defined above, or
R24 and R25, together with the carbon atom to which they are attached form an optionally substituted (cycloalkyl group or heterocycloalkyl group);
X1 is as defined above;
Y is oxygen or sulphur;
Lxe2x80x2 is optionally substituted (xe2x80x94Hetxe2x80x94CH2xe2x80x94 or xe2x80x94CH2xe2x80x94Hetxe2x80x94),
wherein Het is a a hetero atom selected from O, N or S, and
x is 1 or 0,
provided that when x is one, L is xe2x80x94CH2xe2x80x94Oxe2x80x94 and X1 is xe2x80x94C(O)xe2x80x94,
R20 is not unsubstituted phenyl,
provided that when R22xe2x95x90R24xe2x95x90R25xe2x95x90H, x is zero and X, is xe2x80x94C(O)xe2x80x94,
R23 is not H, xe2x80x94CH3, xe2x80x94CH(CH3)2, xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, xe2x80x94CH2xe2x80x94COOH, or xe2x80x94CH2xe2x80x94COOxe2x80x94CH2xe2x80x94CH3, when R20 is unsubstituted phenyl,
R23 is not H, xe2x80x94CH(CH3)2, or xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, when R20 is 4-aminophenyl or 4-nitrophenyl,
R23 is not H when R20 is 3-amninophenyl, 3-nitrophenyl 2-chloropyridin-4-yl, or vinyl, or
R23 is not xe2x80x94CH2xe2x80x94CH2xe2x80x94Sxe2x80x94CH3 when R20 is pyridin-3-yl or 2-chloropyridin-4-yl,
provided that when R22xe2x95x90R23xe2x95x90R24xe2x95x90H, x is zero and X1 is xe2x80x94C(O)xe2x80x94 and R20 is phenyl,
R25 is not xe2x80x94CH(CH3)2,
provided that when R23xe2x95x90R24xe2x95x90H, R25 is xe2x80x94CH2xe2x80x94CH2xe2x80x94COOH, x is zero and X1 is xe2x80x94C(O)xe2x80x94,
R22 does not form a heterocyclic ring with the adjacent nitrogen atom, and
provided that when R22xe2x95x90R23xe2x95x90R24xe2x95x90R25xe2x95x90H, x is zero and X1 is xe2x80x94SO2xe2x80x94,
R20 is not 4-methylphenyl.
Compounds of formula II are typically inhibitors of cathepsins K, L or S, especially selective inhibitors of catepsin K or cathepsin L or cathepsin S, or in some case inhibitors of, e.g. cathepsins L and S.
The substituents of the compounds of formula II have the following preferred significances. Preferred compounds of formula II comprise compounds having preferred substituents, singly or in any combination.
Preferably when R20 comprises aryl, the aryl is optionally substituted (phenyl, naphthylenyl, phenanthrenyl, thiophenyl, furanyl, pyrrolyl, pyrazolyl, thiazolyl, pyridinyl, indolyl, quinolinyl, isoquinolinyl, benzothienyl and benzofuranyl).
Preferably R22 is hydrogen.
Preferably R23 is optionally substituted (lower alkyl, aryl-lower alkyl or cycloalkyl-lower alkyl), or R23 and R22 together with the carbon atom to which they are attached form a C5-C8, especially a C6 or C7, cycloalkylgroup. More preferably R23 is xe2x80x94CH2xe2x80x94CH(CH3)2, or optionally substituted benzyl, cyclohexylmethyl, naphthalenylmethyl, indolylmethyl, benzothienylmethyl or benzofuranylmethyl, or R23 and R22 together with the carbon atom to which they are attached form a cyclohexane ring.
Preferred significances for R24 and R25 are:
R24 and R25 are both H or xe2x80x94CH3, or
R24 is H and R25 is aryl-lower alkyl, lower alkyl, both optionally substitued by up to 3 substituents selected from amino, halogen (e.g. fluorine or preferably chlorine) or Sxe2x80x94CH3, or
R24 and R25 together with the carbon atom to which they are attached form a C3-C7 cycloalkyl ring.
More preferably R24 is H and R25 is optionally substituted (xe2x80x94CH2-phenyl, xe2x80x94CH2-indolyl, xe2x80x94(CH2)2xe2x80x94Sxe2x80x94CH3, xe2x80x94CH2xe2x80x94CH(CH3)2, xe2x80x94(CH2)4xe2x80x94NH2 or xe2x80x94(CH2)3xe2x80x94CH3), or yet more preferably R4 and R5 are both xe2x80x94CH3, or especially R4 and R5 are both H.
Preferably xe2x80x94X1xe2x80x94 is xe2x80x94C(O)xe2x80x94.
Preferably Y isxe2x95x90O.
Preferably either x is 0, or when x is 1 Lxe2x80x2 is xe2x80x94CH2xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94CH2xe2x80x94, xe2x80x94Oxe2x80x94CH2xe2x80x94 or xe2x80x94Sxe2x80x94CH2.
In particular embodiments the invention provides a compound of formula IIxe2x80x2 or a physiologically-acceptable and -cleavable ester or a salt thereof 
wherein:
R20xe2x80x2 is optionally substituted (C6-C18 aryl or C4-C18 heteroaryl);
R22xe2x80x2 is H, or optionally substitued C1-C8 alkyl, and
R23xe2x80x2 is optionally substituted (C2-C8 alkyl, or C7-C14 aralkyl), or
R22xe2x80x2 and R23xe2x80x2 together with the carbon atom to which they are attached form an optionally substituted (C3-C8 cycloalkyl group or C4-C7 heterocycloalkyl group);
R24xe2x80x2 and R25xe2x80x2 are independently H, or optionally substituted (C1-C8 alkyl, C7-C14 aralkyl, or C5-C14 heteroaralkyl), xe2x80x94C(O)OR6xe2x80x2, or xe2x80x94C(O)NR6xe2x80x2R7xe2x80x2
xe2x80x83wherein
R6xe2x80x2 is optionally substituted (C1-C8 alkyl, C7-C14 aralkyl, C3-C8 cycloalkyl, C4-C7 heterocycloalkyl, C5-C14 heteroaralkyl, C6-C14 aryl, or C4-C14 heteroaryl), and
R7xe2x80x2 is H, or optionally substituted (C1-C8 alkyl, C7-C14 aralkyl, C3-C8 cycloalkyl, C4-C7 heterocycloalkyl, C5-C14 heteroaralkyl, C6-C14 aryl, or C4-C14 heteroaryl), or
R24xe2x80x2 and R25xe2x80x2 together with the carbon atom to which they are attached form an optionally substituted (C3-C8 cycloalkyl group or C4-C7 heterocycloalkyl group);
X1 is xe2x80x94C(O)xe2x80x94, xe2x80x94C(S)xe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, xe2x80x94P(O)(OR6xe2x80x2)xe2x80x94
wherein Rxe2x80x2 is as defined above;
Y is oxygen or sulphur;
Lxe2x80x2 is optionally substituted (xe2x80x94Hetxe2x80x94CH2xe2x80x94 or xe2x80x94CH2xe2x80x94Hetxe2x80x94),
wherein Het is a a hetero atom selected from O, N or S, and x is 1 or 0,
provided that when x is one, Lxe2x80x2 is xe2x80x94CH2xe2x80x94Oxe2x80x94 and X1 is xe2x80x94C(O)xe2x80x94
R20xe2x80x2 is not unsubstituted phenyl,
provided that when R22xe2x80x2xe2x95x90R24xe2x80x2xe2x95x90R25xe2x80x2xe2x95x90H, x is zero and X1 is xe2x80x94C(O)xe2x80x94,
R23xe2x80x2 is not H, xe2x80x94CH3, xe2x80x94CH(CH3)2, xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, xe2x80x94CH2xe2x80x94COOH, or xe2x80x94CH2xe2x80x94COOxe2x80x94CH2xe2x80x94CH3, when R20xe2x80x2 is unsubstituted phenyl,
R23xe2x80x2 is not H, xe2x80x94CH(CH3)2, or xe2x80x94CH2xe2x80x94CHxe2x80x94(CH3)2, when R20xe2x80x2 is 4-aminophenyl or 4-nitrophenyl,
R23xe2x80x2 is not H when R20xe2x80x2 is 3-aminophenyl, 3-nitrophenyl, 2-chloropyridin-4-yl, or vinyl, or
R23xe2x80x2 is not xe2x80x94CH2xe2x80x94CH2xe2x80x94Sxe2x80x94CH3 when R20xe2x80x2 is pyridin-3-yl or 2-chloropyridin-4-yl,
provided that when R22xe2x80x2xe2x95x90R23xe2x80x2xe2x95x90R24xe2x80x2xe2x95x90H, x is zero and X1 is xe2x80x94C(O)xe2x80x94 and R20xe2x80x2 is phenyl,
R25xe2x80x2 is not xe2x80x94CH(CH3)2,
provided that when R23xe2x80x2xe2x95x90R24xe2x80x2xe2x95x90H, R25xe2x80x2 is xe2x80x94CH2xe2x80x94CH2xe2x80x94COOH, x is zero and X1 is xe2x80x94C(O)xe2x80x94,
R20xe2x80x2 does not form a heterocyclic ring with the adjacent nitrogen atom, and
provided that when R22xe2x80x2xe2x95x90R23xe2x80x2xe2x95x90R24xe2x80x2xe2x95x90R25xe2x80x2 H, x is zero and X1 is xe2x80x94SO2xe2x80x94,
R20xe2x80x2 is not 4-methylphenyl.
Compounds of formula IIxe2x80x2 are typically selective inhibitors of cathepsin K.
In a further aspect the invention provides a compound of formula III 
wherein
R30 is an acyl group derived from an organic carboxylic, carbonic, carbamic or sulfonic acid;
R32 and R33 are independently hydrogen, lower alkyl, cycloalkyl, bicycloalkyl, or (aryl, biaryl, cycloalkyl or bicycloalkyl)-lower alkyl; or R32 and R33 together represent lower alkylene so as to form a ring together with the carbon to which they are attached;
R34 is hydrogen or lower alkyl; X2,Y1, Ar, Q, Z, n and p are as previously defined;
and pharmaceutically acceptable salts and esters thereof for use as a pharmaceutical.
In preferred embodiments the invention further provides a compound of formula III as defined above, wherein R30 is an acyl group derived from an organic carboxylic, carbamic or sulfonic acid Compounds of formula III are typically selective inhibitors of cathepsin B and/or L.
Particular embodiments relate to the compounds of formula III wherein R30, R32, R33, R34, Q, Z and n are as defined above; and wherein
(a) p is one;
(b) Y1 is O, S, SO, SO2, N(R6)SO2 or Nxe2x80x94R6; and
(c) X2 is lower alkylene; or when n is zero, X2 is also C2-C7-alkylene interrupted by O, S, SO, SO2 or NR6;
wherein R6 is as defined above and pharmaceutically acceptable salts thereof.
Further particular embodiments relate to the compounds of formula III wherein R30, R32, R33, R34, R35, Ar, Z and Q have meaning as defined above; and wherein
(a) p is one, n is zero, and X2 is lower alkylene or C2-C7-alkylene interrupted by O, S, SO, SO2NR6, NR6SO2, SO2NR6, CONR6 or NR6CO; or
(b) p is one, n is one, X2 is lower alkylene and Y1 is O, S, SO, SO2, N(R)SO2 or NR6, SO2NR6, CONR6, NR6CO; or
(c) p is one, n is zero and X2 is lower alkylene; or
(d) p is one, n is zero and X2 is C2-C7-alkylene interrupted by O, S, SO, SO2 or NR6, SO2NR6, CONR6 or NR2CO; or
(e) p is zero, n is one, X2 is lower alkylene and Y1 is O, S, SO, SO2, N(R6)SO2 or NR6, SO2NR6, CONR6 or NR6CO; or
(f) p is zero, n is zero and X2 is C2-C7-alkylene interrupted by O, S, SO, SO2 or NR6, SO2NR6, CONR6 or NR6CO;
and pharmaceutically acceptable salts thereof: or
Preferred compounds of formula III are those in which Z is carboxyl or carboxyl derivatized as a pharmaceutically acceptable ester.
A particular embodiment of the invention relates to the compounds of formula III wherein n is zero, in particular those of formula IIIxe2x80x2
wherein
R30, X2, Ar, Q, and p are as defined above; and wherein
R33xe2x80x2 is carbocyclic or heterocyclic aryl-lower alkyl;
Zxe2x80x2 is hydroxy, acyloxy, carboxyl, carboxyl derivatized as a pharmaceutically acceptable ester or amide, or 5-tetrazolyl;
and pharmaceutically acceptable salts thereof.
In a specific embodiment of the compounds of formula IIIxe2x80x2, R30 is carboxylic acid derived acyl; R33xe2x80x2 is carbocyclic or heterocyclic aryl-lower alkyl; X2 is C1-C5-alkylene, or X2 is C2-C4-alkylene interrupted by O or S; p is one; Ar is carbocyclic arylene; Q is a direct bond or C1-C4-alkylene; and Z is carboxyl or carboxyl derivatized as a pharmaceutically acceptable ester; and pharmaceutically acceptable salts thereof.
In a more specific embodiment of the compounds of formula IIIxe2x80x2, R30 is aroyl, R33xe2x80x2 is carbocyclic aryl-methyl; X2 is C3-alkylene; or X2 is C2-alkylene interrupted by O; p is one; Ar is phenylene; Q is a direct bond; and Z is carboxyl; and pharmaceutically acceptable salts thereof.
A further particular embodiment of the invention relates to the compounds of formula III wherein n is one, in particular those of formula IIIxe2x80x3
wherein
R30, R33xe2x80x2, Y1, Ar, and Zxe2x80x2 are as defined above;
X2xe2x80x2 is lower alkylene;
Qxe2x80x2 is a direct bond or lower alkylene;
and pharmaceutically acceptable salts thereof.
A specific embodiment of the invention is directed to the compounds of formula IIIxe2x80x3 wherein R30 is carboxylic acid derived acyl; R33xe2x80x2 is carbocyclic or heterocyclic aryl-lower alkyl; X2xe2x80x2 isC1-C4-alkylene; Y1 is O or S; Ar is carbocyclic arylene; Qxe2x80x2 is a direct bond or C1-C4-alkylene; and Zxe2x80x2 is carboxyl or carboxyl derivatized as a pharmaceutically acceptable ester; and pharmaceutically acceptable salts thereof.
A more specific embodiment of the invention is directed to said compounds of formula IIIxe2x80x3 wherein R30 is aroyl, R33xe2x80x2 is carbocyclic aryl-methyl; X2xe2x80x2 is C2-alkylene; Y1 is O; Ar is phenylene; Qxe2x80x2 is a direct bond; and Zxe2x80x2 is carboxyl, and pharmaceutically acceptable salts thereof.
A yet further aspect of the invention is directed to a compound of formula IV 
wherein
R4 (is substituted phenyl or heterocyclic aryl, (mono- or di- carbocyclic or heterocyclic aryl)-lower alkyl or lower alkenyl, or heterocyclyl;
R42 is hydrogen or lower alkyl;
R43 is carbocyclic or heterocyclic aryl-lower alkyl;
R44 and R45 are independently hydrogen or lower alkyl; or
R44 and R45 combined represent lower alkylene;
and pharmaceutically acceptable salts and esters thereof.
Preferred are compounds of formula IV wherein R40 is morpholino, substituted phenyl or heterocyclic aryl; R42 is hydrogen; R43 is carbocyclic or heterocyclic aryl-lower alkyl; R44 and R45 are hydrogen or lower alkyl; or R44 and R45 combined represent ethylene to form a cyclopropyl ring.
Particularly preferred are compounds of formula IV wherein R40 is pyrazolyl or pyrazolyl substituted by 1-3 lower alkyl; R42 is hydrogen; R43 is carbocyclic or heterocyclic aryl-C1-C4-alkyl; and R44 and R45 are hydrogen; or R44 and R45 combined are ethylene.
Compounds of formula IV are typically selective inhibitors of cathepsin L and/or S.
The compounds of formulae I, II, III and IV, depending on the nature of substituents, possess one or more asymmetric carbon atoms. The resulting diastereomers and enantiomers are encompassed by the instant invention. Preferably, however, e.g. for pharmaceutical use in accordance with the invention, the compounds of formulae I, II, III and IV are provided in pure or substantially pure epimeric form, e.g. as compositions in which the compounds are present in a form comprising at least 90%, e.g. preferably at least 95% of a single epimer (i.e. comprising less than 10%, e.g. preferably less than 5% of other epimeric forms).
Preferred compounds of formula I are those wherein the asymmetric carbon to which are attached R2 and/or R3 corresponds to that of an L-amino acid precursor and the asymmetric carbon to which is attached the cyano group also corresponds to that of an L-amino acid and is generally assigned the (S)-configuration. Preferred compounds of formula I wherein R3 and R4 represent hydrogen can be represented by formulae V, Vxe2x80x2 and Vxe2x80x3, corresponding to preferred compounds of formulae II, III and IV respectively.
Thus in particularly preferred embodiments the invention provides a compound of formula V, Vxe2x80x2 or Vxe2x80x3
wherein the symbols are as defined above, and
physiologically-acceptable and -cleavable esters or salts thereof.
The compounds of formula I, II, IIxe2x80x2, III, IIIxe2x80x2, IIIxe2x80x3, IV, V, Vxe2x80x2 and Vxe2x80x3 as defined above are hereinafter referred to as Compounds of the Invention.
The general definitions used herein have the following meaning within the scope of the invention, unless otherwise specified.
The term xe2x80x9clowerxe2x80x9d referred to above and hereinafter in connection with organic radicals or compounds respectively defines such as branched or unbranched with up to and including 7, preferably up to and including 4 and advantageously one or two carbon atoms.
A lower alkyl group is branched or unbranched and contains 1 to 7 carbon atoms, preferably 1-4 carbon atoms. Lower alkyl represents for example methyl, ethyl, propyl, butyl, isopropyl or isobutyl.
Lower alkenyl represents either straight chain or branched alkenyl of 2 to 7 carbon atoms, preferably 24 carbon atoms, e.g. as vinyl, propenyl, isopropenyl, butenyl, isobutenyl or butadienyl.
Lower alkynyl represents either straight chain or branched alkynyl of 2 to 7 carbon atoms, preferably 2-4 carbon atoms, e.g. as acetylenyl, propynyl, isopropynyl, butynyl or isobutynyl.
Lower alkyl, lower alkenyl and lower alkynyl may be substituted by up to 3 substituents selected from lower alkoxy, aryl, hydroxy, halogen, cyano, or trifluoromethyl.
Lower alkylene represents either straight chain or branched alkylene of 1 to 7 carbon atoms and represents preferably straight chain alkylene of 1 to 4 carbon atoms, e.g. a methylene, ethylene, propylene or butylene chain, or said methylene, ethylene, propylene or butylene chain mono-substituted by C1-C3-alkyl (advantageously methyl) or disubstituted on the same or different carbon atoms by C1-C3-alkyl (advantageously methyl), the total number of carbon atoms being up to and including 7.
A lower alkoxy (or alkyloxy) group preferably contains 14 carbon atoms, advantageously 1-3 carbon atoms, and represents for example ethoxy, propoxy, isopropoxy, or most advantageously methoxy.
Halogen (halo) preferably represents chloro or fluoro but may also be bromo or iodo.
An acyl group as represented by R30 is preferably derived from an organic carbonic acid, an organic carboxylic acid, a carbamic acid or an organic sulfonic acid.
Acyl which is derived from a carboxylic acid represents, for example, carbocyclic or heterocyclic aroyl, cycloalkylcarbonyl, (oxa or thia)-cycloalkylcarbonyl, lower alkanoyl, (lower alkoxy, hydroxy or acyloxy)-lower alkanoyl, (mono- or di- carbocyclic or heterocyclic)-(lower alkanoyl or lower alkoxy-, hydroxy- or acyloxy- substituted lower alkanoyl), or biaroyl.
Carbocyclic aroyl represents, for instance, benzoyl, benzoyl substituted, by one to three substituents selected independently from e.g. halo, trifluoromethyl, lower alkyl, lower alkoxy, hydroxy, methylenedioxy, nitro, di-lower alkylamino, cyano, or carbocyclic aroyl represents e.g. 1- or 2-naphthoyl.
Heterocyclic aroyl represents, for instance, 2-, 3- or 4-pyridylcarbonyl (such as nicotinoyl), furoyl, thienoyl, oxazoloyl, isoxazoloyl, quinoxaloyl, each optionally substituted by e.g. halo, lower alkyl, lower alkoxy or nitro.
(Oxa- or thia)-cyclolalkylcarbonyl is, for example, tetrahydrofuranoyl or tetrahydrothienoyl. Dicarbocyclic or heterocyclic)aryl-lower alkanoyl is, for example, diphenylacetyl or dipyridylacetyl.
Aryl-(lower alkoxy, hydroxy or acyloxy substituted) lower alkanoyl is, for example, phenyl-(2-alkoxy, hydroxy or acyloxy)-acetyl.
Biaroyl is, for example, 2, 3 or 4-biphenylcarbonyl.
Acyl which is derived from an organic carbonic acid is, for example, alkoxycarbonyl, especially lower alkoxycarbonyl, which is unsubstituted or substituted by carbocyclic or heterocyclic aryl or is cycloalkoxycarbonyl, especially C3-C7-cycloalkyloxycarbonyl, which is unsubstituted or substituted by lower alkyl.
Acyl which is derived from a carbamic acid is, for example, aminocarbonyl which is optionally substituted on nitrogen by one or two of lower alkyl, carbocyclic or heterocyclic aryl-lower alkyl, carbocyclic or heterocyclic aryl, or by lower alkylene or lower alkylene interrupted by O or S.
Acyl which is derived from an organic sulfonic acid represents, for example, lower alkylsulfonyl, carbocyclic or heterocyclic arylsulfonyl, carbocyclic or heterocyclic aryl-lower alkysulfonyl, in which aryl is e.g. phenyl, naphthyl or thienyl, such being optionally substituted by, for example, lower alkyl, lower alkoxy, halo, nitro, trifluoromethyl, carboxyl or lower alkoxycarbonyl.
Aryl represents carbocyclic or heterocyclic aryl.
Carbocyclic aryl represents monocyclic, bicyclic or tricyclic aryl, for example phenyl or phenyl mono-, di- or tri-substituted by one, two or three radicals selected from lower alkyl, lower alkoxy, aryl, hydroxy, halogen, cyano, trifluoromethyl, lower alkylenedioxy and oxy-C2-C3-alkylene; or 1- or 2-naphthyl; or 1- or 2-phenanthrenyl. Lower alkylenedioxy is a divalent substituent attached to two adjacent carbon atoms of phenyl, e.g. methylenedioxy or ethylenedioxy. Oxy-C2-C3-alkylene is also a divalent substituent attached to two adjacent carbon atoms of phenyl, e.g. oxyethylene or oxypropylene. An example for oxy-C2-C3-alkylene-phenyl is 2,3-dihydrobenzofuran-5-yl.
Preferred as carbocyclic aryl is naphthyl, phenyl or phenyl mono- or disubstituted by lower alkoxy, phenyl, halogen, lower alkyl or trifluoromethyl, especially phenyl or phenyl mono- or disubstituted by lower alkoxy, halogen or trifluoromethyl, and in particular phenyl.
Examples of substituted phenyl groups as R are, e.g. 4-chlorophen-1-yl, 3,4-dichlorophen-1-yl, 4-methoxyphen-1-yl, 4-methylphen-1-yl, 4-aminomethylphen-1-yl, 4-methoxyethylaminomethylphen-1-yl, 4-hydroxyethylaminomethylphen-1-yl, 4-hydroxyethyl-(methyl)-aminomethylphen-1-yl, 3-aminomethylphen-1-yl, 4-N-acetylaminomethylphen-1-yl, 4-aminophen-1-yl, 3-aminophen-1-yl, 2-aminophen-1-yl, 4-phenyl-phen-1-yl, 4-(imidazol-1-yl)-1-yl, 4-(imidazol-1-ylmethyl)-phen-1-yl, 4-(morpholin-1-yl)-phen-1-yl, 4-(morpholin-1-ylmethyl)-phen-1-yl, 4-(2-methoxyethylaminomethyl)-phen-1-yl and 4-(pyrrolidin-1-ylmethyl)-phen-1-yl, 4-(2-thiophenyl)-phen-1-yl, 4-(3-thiophenyl)-phen-1-yl, 4-(4-methylpiperazin-1-yl)-phen-1-yl, and 4-(piperidinyl)-phenyl and 4-(pyridinyl)-phenyl optionally substituted in the heterocyclic ring.
Heterocyclic aryl represents monocyclic or bicyclic heteroaryl, for example pyridyl, indolyl, quinoxalinyl, quinolinyl, isoquinolinyl, benzothienyl, benzofuranyl, benzopyranyl, benzothiopyranyl, furanyl, pyrrolyl, thiazolyl, oxazolyl, isoxazolyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl, thienyl, or any said radical substituted, especially mono- or di-substituted, by e.g. lower alkyl, nitro or halogen. Pyridyl represents 2-, 3- or 4-pyridyl, advantageously 2- or 3-pyridyl. Thienyl represents 2- or 3-thienyl. Quinolinyl represents preferably 2-, 3- or 4-quinolinyl. Isoquinolinyl represents preferably 1-, 3- or 4-isoquinolinyl. Benzopyranyl, benzothiopyranyl represent preferably 3-benzopyranyl or 3-benzothiopyranyl, respectively. Thiazolyl represents preferably 2- or 4-thiazolyl, advantageously 4-thiazolyl. Triazolyl is preferably 1-, 2- or 5-(1,2,4-triazolyl). Tetrazolyl is preferably 5-tetrazolyl.
Preferably, heterocyclic aryl is pyridyl, indolyl, quinolinyl, pyrrolyl, thiazolyl, isoxazolyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl, thienyl, or any said radical substituted, especially mono- or di-substituted, by lower alkyl or halogen; and in particular pyridyl.
Arylene (Ar in formula III) is an aryl linking group in which aryl is heterocyclic or carbocyclic aryl, preferably monocyclic as defined above.
A heterocyclic aryl linking group is for instance (but not limited thereto) 1,3-pyrazolyl, 2,4- or 2,5-pyridyl or 1,4-imidazolyl in which the groups as depicted in formula III are attached to the ring at the indicated positions.
A carbocyclic aryl linking group is for instance (but not limited thereto) optionally substituted phenyl in which the two groups as depicted in formula I are attached ortho, meta or para to each other.
Biaryl is may be carbocyclic biaryl, preferably e.g. biphenyl, namely 2, 3 or 4-biphenyl, advantageously 4-biphenyl, each optionally substituted by e.g. lower alkyl, lower alkoxy, halogen, trifluoromethyl or cyano, or heterocyclic-carbocyclic biaryl, preferably e.g. thienylphenyl, pyrrolylphenyl and pyrazolylphenyl.
Cycloalkyl represents a saturated cyclic hydrocarbon optionally substituted by lower alkyl which contains 3 to 10 ring carbons and is advantageously cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl optionally substituted by lower alkyl.
Bicycloalkyl is for example norbomanyl.
Heterocyclyl represents a saturated cyclic hydrocarbon containing one or more, preferably 1 or 2, hetero atoms selected from O, N or S, and from 3 to 10, preferably 5 to 8, ring atoms; for example, tetrahydrofuranyl, tetrahydrothienyl, tetrahydropyrrolyl, piperidinyl, piperazinyl or morpholino.
Aryl-lower alkyl represents preferably (carbocyclic aryl or heterocylic aryl)-lower alkyl.
Carbocyclic aryl-lower alkyl represents preferably straight chain or branched aryl-C1-4-alkyl in which carbocyclic aryl has meaning as defined above, e.g. benzyl or phenyl-(ethyl, propyl or butyl), each unsubstituted or substituted on phenyl ring as defined under carbocyclic aryl above, advantageously optionally substituted benzyl, e.g. benzyl substituted or phenyl lay lower alkyl.
Heterocyclic aryl-lower alkyl represents preferably straight chain or branched heterocyclic aryl-C1-4-alkyl in which heterocyclic aryl has meaning as defined above, e.g. 2-, 3- or 4-pyridylmethyl or (2, 3- or 4-pyridyl)-(ethyl, propyl or butyl); or 2- or 3-thienylmethyl or (2- or 3-thienyl)-(ethyl, propyl or butyl); 2-, 3- or 4-quinolinylmethyl or (2-, 3- or 4-quinolinyl)-(ethyl, propyl or butyl); or 2- or 4-thiazolylmethyl or (2- or 4-thiazolyl)-(ethyl, propyl or butyl).
Cycloalkyl-lower alkyl represents e.g. (cyclopentyl- or cyclohexyl)-(methyl or ethyl).
Biaryl-lower alkyl represents e.g. 4-biphenylyl-(methyl or ethyl).
Acyl as in acyloxy is derived from an organic carboxylic acid, carbonic acid or carbarnic acid. Acyl represents e.g. lower alkanoyl, carbocyclic aryl-lower alkanoyl, lower alkoxycarbonyl, aroyl, di-lower alkylaminocarbonyl or di-lower alkylamino-lower alkanoyl. Preferably, acyl is lower alkanoyl.
Lower alkanoyl represents e.g. C1-7-alkanoyl including formyl, and is preferably C2-4-alkanoyl such as acetyl or propionyl.
Aroyl represents e.g. benzoyl or benzoyl mono- or di-substituted by one or two radicals selected from lower alkyl, lower alkoxy, halogen, cyano and trifluoromethyl; or 1- or 2-naphthoyl; and also e.g. pyridylcarbonyl.
Lower alkoxycarbonyl represents preferably C1-4-alkoxycarbonyl, e.g. ethoxycarbonyl.
Esterified carboxyl is carboxyl derivatized as a pharmaceutically acceptable ester, for example lower alkoxycarbonyl, benzyloxycarbonyl or allyloxycarbonyl.
Amidated carboxyl is carboxyl derivatized as a pharmaceutically acceptable amide, for example aminocarbonyl, mono- or di-lower alkylaminocarbonyl.
Pharmaceutically acceptable salts of the acidic compounds of the invention are salts formed with bases, namely cationic salts such as alkali and alkaline earth metal salts, such as sodium, lithium, potassium, calcium, magnesium, as well as ammonium salts, such as ammonium, trimethyl-ammonium, diethylammonium, and tris-(hydroxymethyl)-methyl-ammonium salts.
Similarly acid addition salts, such as of mineral acids, organic carboxylic and organic sulfonic acids e.g. hydrochloric acid, methanesulfonic acid, maleic acid, are also possible provided a basic group, such as pyridyl, constitutes part of the structure.
The compounds of the invention exhibit valuable pharmacological properties in mammals and are particularly useful as cysteine cathepsin inhibitors.
The cathepsin inhibitory effects of the compound of the invention can be determined in vitro by measuring the inhibition of e.g. recombinant human cathepsins B, K, L and S. The buffer used in the cathepsin B, L and S assays is a 0.1 M pH 5.8 phosphate buffer containing EDTA (1.33 mM), DTT (2.7 mM) and Brij (0.03%).
The in vitro assays are carried out as follows:
(a) For cathepsin B:
To a microtiter well is added 100 uL of a 20 uM solution of inhibitor in assay buffer followed by 50 uL of a 6.4 mM solution of Z-Arg-Arg-AMC substrate (Peptides International) in assay buffer. After mixing, 50 uL of a 0.544 nM solution of recombinant human cathepsin B in assay buffer is added to the well, yielding a final inhibitor concentration of 10 uM. Enzyme activity is determined by measuring fluorescence of the liberated aminomethylcoumarin at 440 nM using 380 nM excitation, at 20 minutes. % Enzyme inhibition is determined by comparison of this activity to that of a solution containing no inhibitor. Compounds are subsequently subjected to a dose response curve analysis to determine IC50 values.
(b) For cathepsin K:
The assay is performed in 96 well microtiter plates at ambient temperature using recombinant human cathepsin K. Inhibition of cathepsin K is assayed at a constant enzyme (0.16 nM) and substrate concentration (54 mM Z-Phe-Arg-MCAxe2x80x94Peptide Institute Inc. Osaka, Japan) in 100 mM sodium phosphate buffer, pH 7.0, containing 2 mM dithiothreitol, 20 mM Tween 80 and 1 mM EDTA. Cathepsin K is preincubated with the inhibitors for 30 min, and the reaction is initiated by the addition of substrate. After 30 min incubation the reaction is stopped by the addition of E-64 (2 mM), and fluorescence intensity is read on a multi-well plate reader at excitation and emission wavelengths of 360 and 460 nm, respectively.
(c) For cathepsin L:
Recombinant human cathepsin L is activated prior to use in this assay: To 500 uL of a 510 nM solution of cathepsin L in a 50 mM pH 5.0 acetate buffer containing 1 mM EDTA, 3 mM DTT and 150 mM NaCl is added 10 uL of a 625 uM solution of dextran sulfate (ave. mw=8000), and the resulting solution is incubated on ice for 30 min. 4 uL of this solution is then diluted into 46 uL assay buffer, yielding a 40 nM enzyme solution.
To perform the assay, 100 uL of a 20 uM solution of inhibitor in assay buffer is added to a microtiter well. 50 uL of a 20 uM solution of Z-Phe-Arg-AMC (Peptides International) is then added. After mixing, 50 uL of the activated 40 nM solution of recombinant human cathepsin L in assay buffer is then added to the well, yielding a final inhibitor concentration of 10 uM. Enzyme activity is determined by measuring fluorescence of the liberated aminomethylcoumarin at 440 nM using 380 nM excitation of 20 minutes. % Enzyme inhibition is determined by comparison of this activity to that of a solution containing no inhibitor. Compounds are subsequently subjected to a dose response curve analysis to determine IC50 values.
(d) For cathepsin S:
To a microtiter well is added 100 uL of a 20 uM solution of inhibitor is assay buffer. 50 uL of a 700 uM solution of Z-Val-Val-Arg-AMC substrate (Peptides International) is then added. After mixing, 50 uL of a 5.2 nM solution of recombinant human cathepsin S in assay buffer is then added to the well, yielding a final inhibitor concentration of 10 uM. Enzyme activity is determined by measuring fluorescence of the liberated aminomethylcoumarin at 440 nM using 380 nM excitation at 200 minutes. % Enzyme inhibition is determined by comparison of this activity to that of a solution containing no inhibitor. Compounds are subsequently subjected to a dose response curve analysis to determine IC50 values.
In view of their activity as inhibitors of cysteine cathepsin enzymes, Compounds of the Invention are particularly useful in mammals as agents for treatment and prophylaxis of diseases and medical conditions involving elevated levels of cathepsins. Such diseases include diseases involving infection by organisms such as pneumocystis carinii, trypsanoma cruzi, trypsanoma brucei, crithidia fusiculata, as well as parasitic diseases such as schistosomiasis and malaria, tumours (tumour invasion and tumour metastasis), and other diseases such as metachromatic leukodystrophy, muscular dystrophy, amytrophy and similar diseases.
Cathepsins, in particular K, have been implicated in diseases of excessive bone loss, and thus the Compounds of the Invention may be used for treatment and prophylaxis of such diseases, including osteoporosis, gingival diseases such as gingivitis and periodontitis, Paget""s disease, hypercalcemia of malignancy, e.g. tumour-induced hypercalcemia and metabolic bone disease. Also the Compounds of the Invention may be use for treatment or prophylaxis of diseases of excessive cartilage or matrix degradation, including osteoarthritis and rheumatoid arthritis as well as certain neoplastic diseases involving expression of high levels of proteolytic enzymes and matrix degradation.
Compounds of the Invention, are also indicated for preventing or treating coronary disease, atherosclerosis (including atherosclerotic plaque rupture and destabilization), autoimmune diseases, respiratory diseases and immunologically mediated diseases (including transplant rejection).
Compounds of the Invention, in particular cathepsin K selective inhibitor compounds, are particularly indicated for preventing or treating osteoporosis of various genesis (e.g. juvenile, menopausal, post-menopausal, post-traumatic, caused by old age or by cortico-steroid therapy or inactivity).
Beneficial effects are evaluated in in vitro and in vivo pharmacological tests generally known in the art, and as illustrated herein.
The above cited properties are demonstrable in in vitro and in vivo tests, using advantageously mammals, e.g. rats, mice, dogs, or isolated organs and tissues, as well as mammalian enzyme preparations, either natural or prepared by e.g. recombinant technology. Compounds of the Invention can be applied in vitro in the form of solutions, e.g. preferably aqueous solutions or suspensions, and in vivo either enterally or parenterally, advantageously orally, e.g. as a suspension or in aqueous solution, or as a solid capsule formulation. The dosage in vitro may range between about 10xe2x88x925 molar and 10xe2x88x929 molar concentrations. The dosage in vivo may range, depending on the route of administration, between about 0.1 and 100 mg/kg.
The antiarthritic efficacy of the compounds of the invention for the treatment of rheumatoid arthritis can be determined using models such as or similar to the rat model of adjuvant arthritis, as described previously (R. E. Esser, et. al. J. Rheumatology, 1993, 20, 1176.)
The efficacy of the compounds of the invention for the treatment of osteoarthritis can be determined using models such as or similar to the rabbit partial lateral meniscectomy model, as described previously (Colombo et al. Arth. Rheum. 1993 26, 875-886). The efficacy of the compounds in the model can be quantified using histological scoring methods, as described previously (O""Byme et al. Inflamm Res 1995, 44, S117-S118).
The efficacy of the compounds of the invention for the treament of osteoporosis can be determined using an animal model such as the ovarectomised rat or other similar species in which test compounds are administered to the animal and the presence of markers of bone resorption are measured in urine or serum.
The compounds of the invention are prepared by:
(a) converting an amide of the formula VI 
xe2x80x83wherein R, R2, R3, R4 and R5 have meaning as previously defined for the compounds of formula I to a nitrile of formula I; or
(b) condensing a compound of the formula VII 
xe2x80x83wherein R4 and R5 have meaning as defined hereinabove, with an acid of formula VIII 
xe2x80x83wherein R, R2 and R3 have meaning as defined above; or with a reactive derivative thereof; or
(c) condensing a compound of the formula Ia 
xe2x80x83wherein R2, R3, R4 and R5 have meaning as defined hereinabove with an acid corresponding to the group Rxe2x80x94[L]xxe2x80x94Xxe2x80x94 or with a reactive derivative thereof; and in the above processes, if required, temporarily protecting any interfering reactive groups and then isolating the resulting compound of the invention; and, if desired, converting any resulting compound into another compound of the invention; and/or if desired, converting a resulting compound into a salt or a resulting salt into the free acid or base or into another salt.
Appropriate protecting groups are used for starting compounds and intermediates, for instance as hereinafter described in the Examples.
The conversion of primary amides of formula V to the nitrites of formula I, according to process (a), can be carried out according to methods well known in the art for the dehydration of a primary amide to a nitrile, e.g. with thionyl chloride in the presence of a base. A preferred procedure involves the treatment with oxalyl chloride and pyridine in DMF at or below room temperature as illustrated in the examples.
The starting materials of formula VI can be prepared by condensing an amino acid amide of formula IX 
wherein R4, and R5 have meaning as defined above with an acid of the formula VIII, in protected form as appropriate.
The condensation can be carried out according to methods well-known in the art, e.g. by reacting a mixed anhydride or an acyl halide of the acid of formula VIII e.g. the acid chloride, with an amino acid amide of formula IX, in an inert solvent such as methylene chloride, in the presence of a base, such as an amine like triethylamine or pyridine.
The acylation of an acid of formula VIII with an amino acid amide of formula IX can also be carried out in the presence of a condensing agent such as N-(3-dimethylaminopropyl)-Nxe2x80x2-ethylcarbodiimide, optionally in the presence of e.g. hydroxybenzotriazole or 1-hydroxy-7-azabenzotriazole, and a base such as N-methylmorpholine.
The amino acid amides of formula IX are either known or can be prepared according to methodology known in the art and illustrated herein.
Alternative procedures and conditions may be used; for instance as described in the Examples.
Compounds of the invention are either obtained in the free form, or as a salt thereof if salt forming groups are present.
Acidic Compounds of the Invention may be converted into metal salts with pharmaceutically acceptable bases, e.g. an aqueous alkali metal hydroxide, advantageously in the presence of an ethereal or alcoholic solvent, such as a lower alkanol. Resulting salts may be converted into the free compounds by treatment with acids. These or other salts can also be used for purification of the compounds obtained. Ammonium salts are obtained by reaction with the appropriate amine, e.g. diethylamine, and the like.
Compounds of the Invention having basic groups can be converted into acid addition salts, especially pharmaceutically acceptable salts. These are formed, for example, with inorganic acids, such as mineral acids, for example sulfuric acid, a phosphoric or hydrohalic acid, or with organic carboxylic acids, such as (C1-C4)alkanecarboxylic acids which, for example, are unsubstituted or substituted by halogen, for example acetic acid, such as saturated or unsaturated dicarboxylic acids, for example oxalic, succinic, maleic or fumaric acid, such as hydroxycarboxylic acids, for example glycolic, lactic, malic, tartaric or citric acid, such as amino acids, for example aspartic or glutamic acid, or with organic sulfonic acids, such as (C1-C4)-alkylsulfonic acids (for example methanesulfonic acid) or arylsulfonic acids which are unsubstituted or substituted (for example by halogen). Preferred are salts formed with hydrochloric acid, methanesulfonic acid and maleic acid.
In view of the close relationship between the free compounds and the compounds in the form of their salts, whenever a compound is referred to in this context, a corresponding salt is also intended, provided such is possible or appropriate under the circumstances.
The compounds, including their salts, can also be obtained in the form of their hydrates, or include other solvents used for their crystallization.
The pharmaceutical compositions according to the invention are those suitable for enteral, such as oral or rectal, transdermal, topical, and parenteral administration to mammals, including man, to inhibit cathepsin activity, and for the treatment of cathepsin dependent disorders, in particular inflammation, osteoporosis, rheumatoid arthritis and osteoarthritis, and comprise an effective amount of a pharmacologically active compound of the invention, alone or in combination, with one or more pharmaceutically acceptable carriers.
More particularly, the pharmaceutical compositions comprise an effective cathepsin inhibiting amount of a Compound of the Invention.
The pharmacologically active Compounds of the Invention are useful in the manufacture of pharmaceutical compositions comprising an effective amount thereof in conjunction or admixture with excipients or carriers suitable for either enteral or parenteral application. Preferred are tablets and gelatin capsules comprising the active ingredient together with a) diluents, e.g. lactose, dextrose, sucrose, mannitol, sorbitol, cellulose and/or glycine; b) lubricants, e.g. silica, talcum, stearic acid, its magnesium or calcium salt and/or polyethyleneglycol; for tablets also c) binders e.g. magnesium aluminum silicate, starch paste, gelatin, tragacanth, methylcellulose, sodium carboxymethylcellulose and or polyvinylpyrrolidone; if desired d) disintegrants, e.g. starches, agar, alginic acid or its sodium salt, or effervescent mixtures; and/or e) absorbents, colorants, flavors and sweeteners. Injectable compositions are preferably aqueous isotonic solutions or suspensions, and suppositories are advantageously prepared from fatty emulsions or suspensions. Said compositions may be sterilized and/or contain adjuvants, such as preserving, stabilizing, wetting or emulsifying agents, solution promoters, salts for regulating the osmotic pressure and/or buffers. In addition, they may also contain other therapeutically valuable substances. Said compositions are prepared according to conventional mixing, granulating or coating methods, respectively, and contain about 0.1 to 75%, preferably about 1 to 50%, of the active ingredient.
Tablets may be either film coated or enteric coated according to methods known in the art.
Suitable formulations for transdermal application include an effective amount of a compound of the invention with carrier. Advantageous carriers include absorbable pharmacologically acceptable solvents to assist passage through the skin of the host. For example, transdermal devices are in the form of a bandage comprising a backing member, a reservoir containing the compound optionally with carriers, optionally a rate controlling barrier to deliver the compound of the skin of the host at a controlled and predetermined rate over a prolonged period of time, and means to secure the device to the skin. Matrix transdermal formulations may also be used.
Suitable formulations for topical application, e.g. to the skin and eyes, are preferably aqueous solutions, ointments, creams or gels well-known in the art. Such may contain solubilizers, stabilizers, tonicity enhancing agents, buffers and preservatives.
The pharmaceutical formulations contain an effective cathepsin inhibiting amount of a Compound of the Invention as defined above, either alone or in combination with another therapeutic agent.
In conjunction with another active ingredient, a Compound of the Invention may be administered either simultaneously, before or after the other active ingredient, either separately by the same or different route of administration or together in the same pharmaceutical formulation. The dosage of active compound administered is dependent on the species of warm-blooded animal (mammal), the body weight, age and individual condition, and on the form of administration. A unit dosage for oral administration to a mammal of about 50 to 70 kg may contain between about 5 and 500 mg of the active ingredient.
The present invention also relates to methods of using Compounds of the Invention and their pharmaceutically acceptable salts, or pharmaceutical compositions thereof, in mammals for inhibiting cathepsins, such as cathepsin B, K, L and/or S, and for the treatment of cathepsin dependent conditions, such as cathepsin B, K, L and/or S dependent conditions, described herein, e.g. inflammation, osteoporosis, rheumatoid arthritis and osteoarthritis.
Particularly the present invention relates to a method of selectively inhibiting cathepsin activity in a mammal which comprises administering to a mammal in need thereof an effective cathepsin inhibiting amount of a Compound of the Invention.
More specifically such relates to a method of treating rheumatoid arthritis, osteoarthritis, and inflammation (and other diseases as identified above) in mammals comprises administering to a mammal in need thereof a correspondingly effective amount of a Compound of the Invention.